Expertise and category-based induction

The authors examined inductive reasoning among experts in a domain. Three t ypes of tree experts (landscapers, taxonomists, and parks maintenance perso nnel) completed 3 reasoning tasks. In Experiment 1, participants inferred w hich of 2 novel diseases would affect "more other kinds of trees" and provi ded justifications for their choices. In Experiment 2, the authors used mod ified instructions and asked which disease would be more likely to affect " all trees." In Experiment 3, the conclusion category was eliminated altoget her, and participants were asked to generate a fist of other affected trees . Among these populations, typicality and diversity effects were weak to no nexistent. Instead, experts' reasoning was influenced by "local" coverage ( extension of the property to members of the same folk family) and causal-ec ological factors. The authors concluded that domain knowledge leads to the use of a variety of reasoning strategies not captured by current models of category-based induction.